Implant Prosthesis Notes

  • Prosthetically, anterior and one posterior side implants can be splinted for a fixed prosthesis.
  • The other posterior segment is restored independently with a three-unit fixed prosthesis.
  • Three implants are used for the smaller segment (first premolar, second premolar, and molar).
  • This compensates for force factors and alignment, as they are almost in a straight line.
  • At least six implants are used, often seven, to ensure the smaller segment has three implants.
  • The primary advantage is the elimination of cantilevers, reducing the risk of occlusal overload.
  • Another advantage is having two segments instead of one.
  • The larger segment (molar to contralateral canine) has implants in three to four horizontal planes.
  • No cantilever means less damaging forces are applied.
  • If repair is needed, the affected segment can be removed more easily.
  • Posterior disclusion in excursions limits lateral loads, especially on prostheses with fewer implants.
  • Disadvantages include needing abundant bone in both posterior regions and additional costs for implants.
  • Some modifications include fabricating three independent prostheses: four to five implants in the anterior, two in the first molar sites, two in the first premolar sites, and two in the canine regions.
  • Secondary positions are the two second premolar and central incisor (midline) sites.
  • Posterior restorations extend from the first molar to the first premolar; an anterior restoration replaces the six anterior teeth.
  • Advantages of smaller segments are individual restorations and flexibility/torsion of the mandible.
  • The primary disadvantage includes the greater number of implants required in severe force scenarios.
  • Nine implants are rarely needed, regardless of bone density/force factors.
  • Treatment Option 5: All-on-Four Protocol.
  • was developed to avoid regenerative procedures, treatment costs, and patient morbidity.
  • developed by Malo, uses four anterior implants in the edentulous jaw to support a provisional, fixed, and immediately loaded prosthesis.
  • Most commonly, two anterior implants are placed axially, while two posterior implants are placed at an angle (approximately 45 degrees).
  • This increases A-P spread and decreases cantilever length.
  • Tilted implants generate favorable biomechanical outcomes and have high survival rates with low complications.
  • The tilted implants allow for longer implants, reduce cantilever length, and avoid vital structures like the inferior alveolar canal.
  • it is popular due to the decreased treatment costs and treatment duration.
  • Most dental implant has survival rates of 98%.
  • However, all-on-four protocols require additional surgical/prosthetic skills; clinicians on their learning curve should be cautious.
  • Advantages of unilateral cantilever and increased anteroposterior spread, with adequate posterior bone for high force factors and square arch forms.
  • Treatment option 4 has high support without a cantilever, increasing the anteroposterior spread.
  • Advantages included no cantilever, increased anteroposterior spread, and highest support with bilateral posterior bone for poor bone density.
  • Disadvantages: More implants required and bilateral posterior bone.
  • High survival requires clinicians to have additional surgical/prosthetic skills or augmentation could take place upon failure of the prosthesis.